Institution: | (1) Department of Zoology, University College of North Wales, LL57 2UW Bangor, Gwynedd, UK;(2) Department of Zoology, U.C.N.W., LL57 2UW Bangor, Gwynedd, UK;(3) Present address: Laboratoire d'Histologie et Biologie Tissulaire, Université Claude-Bernard, 43 boulevard du 11 Novembre 1918, 69621 Villeurbanne, France |